SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af7804eb202af070cd6bb84833d50c797f889f9c75ac8a6648698ce34ac2dfd0' 
  AND token = '2thUagIbq8fAfMLAbVIbThrQqQaUJ4cwzgCE1cRAN04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}